Objectives: To estimate the prevalence of psoriatic arthritis (PsA) and associated factors in patients with moderate-to-severe psoriasis. Methods: Retrospective, single-center study of a cohort of psoriasis patients in standard follow-up in a dermatology department from July 2008 to January 2024. Patients ≥18 years with moderate-to-severe psoriasis were included and classified into three groups according to the treatment received: group 1, biologics or small molecules with or without conventional synthetic disease-modifying anti-rheumatic drugs (csDMARDs); group 2, only csDMARDS; and group 3, non-pharmacological treatments. Demographic and clinical variables were collected. The prevalence of PsA was estimated with its 95% confidence interval (CI). The cumulative incidence of PsA was analyzed across groups, and logistic regression models were built. Results: The study population comprised 308 patients (67.2%, 22.7%, 10% in groups 1, 2, and 3, respectively). Differences between the groups were observed in severity of psoriasis, weight, smoking status, and dyslipidemia (p < 0.05). The prevalence of PsA was 11.7% (95% CI, 8.1–15.3), with most patients in group 1. This group had a higher risk of PsA following diagnosis of psoriasis or initiation of treatment. Belonging to groups 2 and 3 had a smaller effect than belonging to group 1 in the development of PsA; nail involvement and obstructive sleep apnea (OSA) were associated with development of PsA (p < 0.05). Conclusions: The prevalence estimate was lower than previous estimates, probably owing to the increased use of biologics. Nail involvement and OSA were associated with PsA.

Objectives: To estimate the prevalence of psoriatic arthritis (PsA) and associated fac-tors in patients with moderate-to-severe psoriasis. Methods: Retrospective, single-center study of a cohort of psoriasis patients in stand-ard follow-up in a dermatology department from July 2008 to January 2024. Patients ≥18 years with moderate-to-severe psoriasis were included and classified into 3 groups according to the treatment received: group 1, biologics or small molecules with or without conventional synthetic disease-modifying anti-rheumatic drugs (csDMARDs); group 2, only csDMARDS; and group 3, non-pharmacological treatments. Demographic and clinical variables were collected. The prevalence of PsA was estimated with its 95% confidence interval (CI). The cumulative incidence of PsA was analyzed across groups, and logistic regression models were built. Results: The study population comprised 308 patients (67.2%, 22.7%, 10% in groups 1, 2, and 3, respectively). Dif-ferences between the groups were observed in severity of psoriasis, weight, smoking status, and dyslipidemia (p< 0.05). The prevalence of PsA was 11.7% (95% CI, 8.1-15.3), with most patients in group 1. This group had a high-er risk of PsA following diagnosis of psoriasis or initiation of treatment. Belonging to groups 2 and 3 had a smaller effect than belonging to group 1 in the development of PsA; nail involvement and obstructive sleep apnea (OSA) were associated with development of PsA (p< 0.05). Conclusions: The prevalence estimate was lower than previous estimates, probably owing to the increased use of biologics. Not requiring biologics for disease control had less effect on development of PsA. Nail involvement and OSA were associated with PsA.